Synthesis, structure, and properties of [nacnac]MX3 compounds (M = Ge, Sn;X = Cl, Br, I)

Reactions of [nacnac]Li [(2,6-(Pr2C6H3)-Pr-i)NC(Me) C(H)C(Me)N(2,6-(Pr2C6H3 )-Pr-i)]Li (1) with SnX4 (X = Cl, Br, I) and GeCl4 in Et2O resulted in meta llacyclic compounds with different structural moieties. In the [nacnac]SnX3 compounds (X = Cl 2, Br 3, 1 4) the tin atom is five coordinated and part of a six membered ring. The Sn-N-bond length of 3 is 2.163(4)Angstrom and 2 .176(5) Angstrom of 4. The five coordinated germanium of the [nacnac]GeCl3 compound 5 shows in addition to the three chlorine atoms further bonds to a carbon and to a nitrogen atom. In contrast to the known compounds with the [nacnac] ligand the afore mentioned reaction creates a carbon-metal-bond ( 1.971(3)Angstrom) forming a four-membered ring. The Ge-N bond length (2.319 (2) Angstrom) indicates the formation of a weakly coordinating bond.